Type 1 diabetes Is an autoimmune disease that occurs when autoreactive T cells attack and kill the insulin producing cells of the pancreas. Currently, the disease is treated by repeated insulin Injections, however there is no cure. Prolonged periods of unstable blood sugar are damaging to numerous organ systems, for this reason complications due to diabetes Is the seventh leading cause of death in the U.S. Improved therapies to treat diabetes would greatly enhance the quality and life expectancy for the millions who suffer from this devastating disease. Immunotherapies are currently the focus of new treatment for diabetes. Drak2 is a serine/threonine kinase primarily expressed in B and T cells. Drak2 deficient (Drak2-/-) mice are remarkably resistant to type 1 diabetes and multiple sclerosis. The resistance to these diseases arises because the autoreactive T cells do not survive in the absence of Drak2. Interestingly, the loss of Drak2 does not impair the survival of T cells responding to foreign pathogens. Thus, we hypothesize Drak2 Is an Ideal target for treating autoimmune disease, without compromising immunity to Infectious agents. However, little is known about the molecular mechanisms of Drak2, and for Drak2 to be a plausible treatment in humans, inhibition of Drak2 must abrogate disease after the onset of symptoms. The experiments proposed In this application will test our hypothesis by identifying the molecular actions of Drak2 to determine If it Is a suitable therapeutic target for treatment of type 1 diabetes. First, we will compare phosphorylated proteins in WT and Drak2-/- T cells that are stimulated through the T cell receptor (TCR). These proteins will be identified by mass spectrometry after enrichment of phosphorylated peptides using magnetic beads. Second, we will identify proteins that immunoprecipitate with Drak2 by mass spectrometry. Next we will create a transgenic mouse that expresses an Inducible Drak2 to test If the loss of Drak2 protein after blood glucose levels increase inhibits disease progression. The work proposed here is directly related to public health and may lead to significantly improved therapies for type 1 diabetes and other autoimmune diseases. These experiments will not only contribute to designing improved treatments for disease, but they will also elucidate the underlying cause of autoimmunity and perhaps uncover a novel mechanism of T cell regulation.